X-ray tube



Filed March 25. 1927 Patented Feb. A27, 1934 x-RAY TUBE Albert Bouwers,Eindhoven, Netherlands, as-

signor to N. V. Philips Gloeilampenfabreken, Eindhoven, Netherlands, alimited liability company -of-the Netherlands Application March 25,

1927, serial No. 178,457

In the Netherlands April 19, 1926 21 Claims.

This invention relates to X-ray tubes which are so constructed that anydanger during the operation of the tubes is avoided, this applicationforming in part a continuation of my copending application, Serial No.5,108, led January 27,

1925. The inconvenience of the X-rays emerging not only in the directionin which they are desirable, butin any direction, has been obviatedbefore by constructing a tube as indicated in the application for patentSerial No. 673,166, November 6, 1923. When operating tubes of thisconstruction the parts which are under high voltage constitute a sourceof danger; This danger is also obviated by the'construction according tothe invention.

It is known to arrange the high tension transformer and the X-ray tube(which is entirely of glass) within a vessel which is entirely lled withoil. The high tension cables are also entirely immersed in the oil.

As a rule X-ray installation constructed in this manner substantiallyproduce-no danger to the patient and to the operator. The disadvantageof such installations is, however, that their volume and weight aregreat when compared with the X-ray energy radiated. One object of theinvention is to provide an improved construction of an X-ray tube whichis entirely protected both with respect to undesired X-rays and to thedanger arising from high tensions. Another object of the invention is toprovide an X-ray tube showing a high activity and reliability, andhaving a relatively small weight. Other advantages willl appear from thenext part of the description.

The X-ray tube according to the invention has an outer wall consistingof a metallic part which is insulated from the electrodes by means of-insulating parts. Said insulatingparts are closely surrounded by ametal envelope, which is designed to be electrically connected toground. The metal envelope may then be connected directly or indirectlyto the metal outer wall. It is possible to also enclose in the saidmetal envelope the part of the high tension cables that extends betweenthe tube and the stand. The aliticathode is provided with a currentsupplying conductor which rapidly carries away the heat and is roundedat the end turned away from the anticathode. The metal envelope is alsorounded a't the ends of the tube and adjacent the anticathode therounded part of the envelope has cooling apertures.

The tube comprises two glass portions united `by a metal part. Thismetal connecting part preferably consists of ferro-chromium, this alloybeing non-porous and eminently suitable to be sealed to glass. Itscomposition should be such that the thermal coefficient of expansion issubstantially identical with that of the glass. The

anticathode is sealed to one of the two glass portions, the otherportion carrying a metal vessel in which the cathode is enclosed. Themetal connecting part is provided with a window for the passage o f theX-rays. The metal part of the outer wall may, if necessary be surroundedby a lead jacket. Apertures for the passage of the high tension cablesare bored at suitable points in the insulating cylinders. Then the tubeand the high tension cables are surrounded by a metal jacket leaving thewindow free so that the entire apparatus has the appearance of oneentirely made of metal.

The metal connecting part of the X-ray tube is connected to ground sothat the total high tension drop occurring between the cathode and theanticathode is. evenly distributed between the anticathode andtheconnecting part, and between the latter and the cathode.

.The accompanying drawing represents, by way of example, a sectionalview of an X-ray tube to which the invention has been applied.

Referring to the said drawing, 1 represents a cathode, 2 an anticathode,3 a metal vessel in which the cathode is arranged, said metal vesselbeing sealed at 14 to a glass tube 7, 4 and 5 are current supplyingwires of the cathode, 6 is the current supplying cable of theanticathode, 8 represents an insulating cylinder. In order that thebreakdown voltage may be increased, the leadingin wire of theanticathode is provided with a rounded end portion 9, the leading-inwires of the cathode being thick for the same reason. This end portionis recessed at 18 so as to permit a satisfactory attachment of the cable6. Ametal envelope 10 is provided with cooling aperture 11. 'I'he cablesare provided with metal' sleeves 12.

The X-ray tube proper comprises a central metal portion 13 to which aresealed at 16 the two glass portions 7-7 of the tube. The metal envelope10 and the metallic central portion 13 are apertured to form a window 15through which the X-rays may emerge,l whereas the X-rays which do notpass through the window, so far as they are not already absorbed by themetal portion`13, are absorbed by a lead jacket 17 surrounding the metalportion 13. The lead jacket is also provided with an aperture for thepassage of the useful rays. Since the grounded metal envelope 10 iselectrically connected to the metal part of the wall through the leadjacket 17, the average electrode potential is equal to ground potential;moreover, due to the wall construction, the electrodes may have nearlysimilar effective voltages in relation to ground. By these means agreater safety is obtained, together with a very practical arrangement,the dimensions of the device being greatly decreased, whilst the entireouter surface of the tube may be touched without any danger.

The current supplying conductor of the anticathode is made of materialthat rapidly conducts away the heat so that this conductor also servesas a cooler of the anticathode. Cooling apertures 11 in the sphericalpart of the metal envelope serve to cool the said conductor. Thedistance between the rounded part of the current supplying conductor ofthe anticathode and the rounded part of the metal envelope should be s ogreat that at the operation tension no breakdown can ensue. In orderthat the breakdown voltage may be increased, the end of the leading-inwire of the anticathode is rounded, the leading-in Wires of the cathodebeing thick for the same reason.

What I claim is:

1. An X-ray tube having electrodes and a wall comprising a metallic partwhich is insulated from said electrodes by means of insulating parts,the tube being closely surrounded by a metal envelope which is designedto be connected to ground and is rounded opposite the ends of the tube,-the rounded part of said metal envelope adjacent the anticathode havingsubstantially the same center of curvature as the adjacent rounded endof the anticathode and being provided with cooling apertures.

2. A unitary structure comprising an X-ray tube having a wall, portionsof which are of metal and glass and a closely surrounding metal envelopespaced from said glass wall portions by insulating parts, said glasswall portions also insulating the metallic part ofthe tube wall from thetube electrodes, said metal envelope being electrically connected to themetallic part of the tube wall and designed to be connected to ground.

3. A unitary structure comprising an X-ray tube having electrodes and awall comprising a metallic part which is insulated from said electrodesby means of insulating parts, and a metallic envelope completelysurrounding the insulating parts and secured to the metallic part of thetube Wall and together with the X-ray tube forming an integral part ofthe unitary structure.

4. A unitary structure comprising an X-ray tube having electrodes and a`wall, portions of which wall are of metal and glass, and a surroundingmetal envelope spaced from said glass wall portions by insulatingpartitions, said metal envelope being in electric connection with themetalllc part of the tube wall and together with the X-ray tube formingan integral part of the unitary structure.

5. A space-discharge tube having a wall comprising insulating portionsand a metallic part, and a metal envelope surrounding said insulatingwall portions throughout their entire length and secured to the metallicpart of the tube wall.

6. A unitary structure comprising an X-ray tube, the said tube having awall formed of a substantially central metal portion and cooperating endportions of insulating material, electrodes for the said tube separatedfrom the metal portion by the insulating portions of the tube, asurrounding metal envelope forming together with the X-ray tube anintegral part of the unitary structure, insulating partitions spacingthe envelope from the said insulating portions of the tube, and a leadjacket disposed between said partitions and in intimate contact withsaid envelope. I

7. A unitary structure comprising a substantially cylindrical X-ray tubehaving a wall formed of metal and glass, and a surrounding metalenvelope having a portion aring outwardly in direction away from themetal portion of the tube, said envelope at its substantially smallestdiameter being connected to said metal portion of the tube.

8. A unitary structure comprising a substan.. tially cylindrical X-raytube having a wall formed of metal and glass, and a surrounding metalenvelope having two substantially frustoconical portions each increasingin diameter in opposite directions away from the metal portion of thetube, said envelope along its substantially smallest diameter beingfixedly connected to said metal portion of the tube wall andperipherally thereof.

9. An X-ray tube having electrodes and a Wall comprising a metallic partwhich is insulated from said electrodes by means of insulating parts,the latter being surrounded throughout their entireA extent by a metalenvelope connected to the metal part of the wall and designed to beconnected to ground.

10. An X-ray tube having electrodes and a wall comprising a metallicpart which is insulated from said electrodes by means of insulatingparts, and a metal envelope designed to be connected to groundsurrounding the insulating parts and connected to the metallic part ofthe wall, the anticathode being provided with a current supplyingconductor which rapidly conducts away the heat and is rounded at the endturned away from the anti-cathode. f

11. An X-ray tube having electrodes and a wall comprising a metallicpart which is insulated from said electrodes by means of insulatingparts, high tension cables leading to said electrodes and metallicsleeves surrounding said cables, a metal envelope surrounding theinsulating parts of the tube and having apertured portions to receivesaid cables, said envelope comprising a waist section which surroundsand electrically contacts the metallic part of the tube,'and supports ineach lateral direction.

12. A unitary structure consisting of an X-ray tube comprisingelectrodes, insulating portions and a ray chamber defined by a metalliccylinder, said electrodes being electrically separated from the saidmetallic cylinder by said insulating portions of the tube, a metalenvelope designed to be electrically connected tothe ground completelysurrounding each of the said insulating wall portions and a sleeveformed of X-ray opaque metal, the said metallic cylinder beingsurrounded by and electrically connected with y said sleeve.

`13. An X-ray tube having an evacuated container of substantialcylindrical shape, electrodes mounted therein and disposed in spacedrelationship to form a discharge gap in the central portion of the tube,an X-ray opaque shield applied to the Wall of the container andextending over said discharge gap and over the active portions of theelectrodes, and a metal envelope closely surrounding said opaque shieldand extending at both sides thereof over the container so as tocompletely surround same, the portions of the envelope extending beyondsaid opaque shield being in spaced relationship to the evacuatedcontainer, to vform an insulating space between the envelope andcontainer.

14. An X-ray tube having an evacuated container, electrodes YVmountedtherein and longitudinally spaced apart to form a discharge gap, saidcontainer being formed with an equipotential waist section surroundingthe discharge gap and the active portions of the electrodes, and a metalenvelope substantially completely surrounding the evacuated containerand showing a reduced middle portion which surrounds said equipotentialwaist section of the container and p is secured and electricallyconnected thereto, said middle portion having an aperture and said waistsection having a ray-pervious window in alignment with said aperture. f

15. An X-ray tube having electrodes comprising a cathode and ananti-cathode and a wall comprising a metallic portion which is insulatedfrom the electrodes'by means of insulating wall portions and ametallicenvelope surrounding the insulating wall portions of the tube andsupporting the tube in the middle portion thereof and designed tobeconnected to ground, said envelope being rounded opposite the ends o fthe tube and forming chambers around said ends, the anticathode chambersbeing provided with ventilating aperture, said anti-cathodehavingconnected to it a heat absorbing body which is rounded at its end.

16. An X-ray tube having electrodes and a wall comprising a metallicpart which is insulated from said electrodes by means of insulatingparts, and a metal envelope designed to be connected to ground,surrounding the insulating parts and connected to the metallic part ofthe wall, and which envelope is rounded at the ends of the tube, therounded part of said metal envelope adjacent the anticathode beingprovided with cooling apertures.

1'7. An X-ray tube having electrodes and a wall comprising a metallicpart which is insulated from said electrodes by means of insulating Wallportions, high tension cables leading to said electrodes and havingmetal sleeves surrounding same, and a metal envelope designed'to beelectrically connected to ground, surrounding the insulating wallportions and having an integrally formed cylindrical middle portionsupporting the metallic part of the tube, and having apertured portionson each side of said cylindrical portion to receive said cables, saidcable sleeves being electrically connected to said metal envelope.

18. An X-ray tube having electrodes and a Wall comprising a metallicpart which is insulated from the electrodes by means of insulating wallportions, and a metal envelope surrounding the insulating wall portionsof the tube in spaced trically contacting the metallic part of the tubeand supports the same in each lateral direction, said envelope beingdesigned to be connected to ground and being rounded opposite the endsof the tube.

19. A unitary structure comprising an X-ray tube having a Wall, acentral portion of which is of metal and portions of which are of glass,and electrodes insulated from the metal portion of the tube wall by theglass portions thereof, a surrounding metal envelope designed to beelectrically connected to ground and together with the X-ray tubeforming an integral part ofthe unitary structure, insulatingpartitionsspacing said metal envelope from said glass wall portions of the tube,said envelope being reduced in its section surrounding the metal portionof the tube, said metal portion being connected to said metal envelopeat the reduced section.

20. A unitary structure comprising a substantially cylindrical X-raytube having electrodes and a wall formed of insulating parts and a metalportion, the latter being insulated from said electrodes by means of theinsulating parts and forming the ray generating chamber of the tube, anda'surrounding metal envelope having two substantially frusto-conicalportions increasing in diameter in opposite directions axially away fromthe metal portion of the tube, a metal sleeve surrounding said metalportion and intermediate to said metal portion and said envelope; thesaid metal portion, the said sleeve, and the said envelope being inelectrical connection with each other and adapted to be connected toground.

21. A unitarystructure comprising a substantially cylindrical X-ray tubehaving insulating portions and an X-ray generating chamber deiined by ametal cylinder, and a surrounding metal envelope designed to beconnected to the ground and having a portion ilaringoutwardly in thedirection away from the metal cylinder, said envelope along itssubstantially smallest diameter portion being connected to said -metal

